1. Field of the Invention
The present invention relates to a digital still camera having an automatic focusing function and to an image processing system which includes the digital still camera and an image processing device.
2. Description of the Related Art
Digital still cameras which have an automatic focusing function are conventionally known. In such a digital still camera, every time the image-capturing lens is driven to capture an image, its focus is detected in accordance with the contrast of the image captured. After the focus detection is completed, the image-capturing lens is driven again to capture an image and detect its focus. To this end, generally employed is a mount-climbing scheme, in which the aforementioned sequence of driving the image-capturing lens to capture an image and detect its focus is repeated until proper focus is achieved (e.g., see Japanese Patent Gazette No. 2786894). Automatic focusing according to such a mount-climbing scheme is successively performed until an image is actually captured after an instruction is provided to initiate the capture of the image.
However, in the automatic focusing according to the aforementioned mount-climbing scheme, the sequence of driving the image-capturing lens to capture an image and then detect its focus is repeated until proper focus is achieved. Thus, a long time is required until an image is actually captured after an instruction is provided to initiate the capture of the image. Additionally, in the automatic focusing according to the mount-climbing scheme, the proper focus position of the image-capturing lens can be known for the first time only after the lens has passed by the proper focus position. Therefore, to capture an image with the image-capturing lens at the proper focus position, the image-capturing lens must be driven back in the opposite direction. Accordingly, the chance to capture the desired image would be missed in some cases.